Apparatus for and method of receiving electric waves.



' ArrARAT'Us POR AND METHOD or BEGAIWNGALEGTRIG WAVES.

APPLIOATIQIF FILED MAILZQ, 1911. vPatented July 21, 1914,

I a subject of the Grand RUDOLF GOLDSCHMIDT, OF DARMSTADT, GERMANY. APPARATUS FOR AND METHOD 0F RECEIVING ELECTRIC -Specification of Letters Patent.

WAVES.

Application led March29, 1911. Serial No. 617,735. i

To allwom it may conce-m.'

Be it known that I, RUDoLrGoLDscnMIDT, Duke of Hesse, and residing at Darmstadt,.in the Grand Duchy of Hesse, German Empire, have invented certain new and useful Improvements in Apparatus for and Method of Receiving lElectric Waves, of which the following is a specitcation. L

The frequency of the waves employed for wireless telegraphy and telephony is too great to be directly perceived in the receivers.

The object of the present invention con` sists 1n' diminishing the frequency of the waves in such a degree that they become capable of being directly perceived in a telephone, or of actuating other apparatus.

In the accompanyingdrawing: Figure 1 is a diagrammatic view ofa frequency-diminishing apparatus embodying my invention; Fig.' 2 a diagram of a modification showing two'- machines in cascade-'connection; Fig. 3 a diagram of a further modification, showing the electrical energy conducted backfrom the' stator to the rotor etc.; Fig. 4 a diagram of a still further 'mod- `iiication showing the rotor and stator employed respectively as primary and secondary parts, and Fig. 5 'a diagram of another modication showing both the primary and secondary parts madev rotatable.

The current coming from the antenna and passing down to the earth E (directly or by mediate circuits with loose -or'fast coupling) is conducted into the stator-coil S, whereas the rotor R preferably lies in a short-circuit 'with a condenser C serving for regulating or pitching purposes. The receiver T of any suitable construction is inserted into .the

rotor-circuitfif desired, in connection withl an intermediate circuit. .If the receiver is actuated from the motor in such a manner that the transformation 'of frequency before mentioned occurs, then the frequency of the motor-currents, slip, may be so chosen that a'musical sound is. produced within the telephone.

The wiring need not, vof course, be such one that the whole current passes'through the receiver. When co'nstructiri.'a such a detector, similar diihculties areencountered as are inherent in generators of high frequency for the reason that the high frequency of the currents employed in wireless telegraphy -the synchronous one'. chine should therefore he constructed similar .differs from the former only by 1% the mediation of transforming interwhich corresponds to the' y' and telephonyrequires a high velocity of .the rotor.-

Today, about 30000 periods (waves of.10000 meters length) represent the lowest frequency employed in wireless telegraphy` Now, in order to produce, for instance, a sound easily perceptible within a telephone, the 30000 periods must be changed to 500 periods, and in order to bring aboutr this low frequency within the rotor, the speed of the latter ought to differ from the synchronous speed only by l I :t'fsoo-og (that means` a slip of 1.67%) in other words, the speed of the motor mus't be nearly The receiving mato a'highlfrequency generator.' With a detector, however, circumstances are somewhat simpler, because the eect of the machine need be but small.

Patented July 21., 1914.

The chief advantage of the induction-ma- I chine when used as detector resides in the, fact that not, as with a ticker, the tickingnoise isheard, but there isl heard a sound or tone which depends upon the wave-length itself. Suppose the'number of 'rotations be such, that at 30000 periods (10000 meters -wave-length) a tone of 500 oscillations per second is produced, then another wave that (9900 meters, corresponding to 30300 periods) would cause atone of 800 oscilla-tions, the

itch'of which .would thus differ by 60% om that produced by the wavel of 10000 meters length. The peculiar behavior of the asynchronous detector to annunciate the difference .between the frequency of 4the rarriving wave andthat of its own number 0frotations in the form of va tone makes this detector particularly adapted to obtain `a greater' freedom from disturbances by other as vwell as from atmospheric disstations, turbances in case the antenna he but slightly out of pitch.l lAnother essential advantage consists in this, that the'same machine may be employed` as sending instrument'in lieu of as receiving instrument, in which 'case the machine is used as asynchronous generator show-n to be .driven by a belt B.

In certain instances, it mav be advantageous to replace the single machine above described by a plurality of machinesv in cascade connection, two of such machines being illustrated in Fig'. 2. Furthermore,

the number of rotations of a single machine' may be reduced by stepwise returning the electrical energy from the stator to the rotor, from the latter to the stator, and so on, as illustrated in Fig. 3. For this purpose, the slip rings of rotor R areby wires a, b not only connected to the rotor winding but also to the Wires c, d that respectively connect the stator Winding to thea'ntennaA and ground E, condensers C being provided for Wires a, b. The speed reduction above referred to is here due to the fact that 'by rel turning the energy, the slip may Abe increased. In other Words, the receiver is not supplied with the current, which is caused by the slip of the rotor relatively to the primary periodicity ofthe energy supplied to the stator but by returning the current to the rotor, the primarv current of high frequency issuperimposed upon the current of the meanwhile reduced slip frequency. In this Way, the receiver is supplied with a current generated by said slip relatively to the second stator current. It may also be desirable in certain cases, to have the stator and rotor exchange their rle as primary and secondary part (Fig. t); or both, the primary and the secondary part may be rotated (Fig.

lHaving now described my invention, what I desire to secure by a patent of the United States is:

l: In Wireless signaling, means-for intercepting the energy of high frequencyy elec tromagnetic Waves radiated through the atthe Waves of reduced frequency are con-V ducted. l

8. Apparatus of the character .described comprising an antenna adapted to ntercept electric Waves of high frequency, an asynchronous transformer, means for conducting said Waves from' the antenna to said transformer, and means for receiving thel -transformed Waves from the transformer to render them perceptive.

4. In Wireless signaling, the method of receiving messages, Which consists in intercepting the energy of high frequency electromagnetic waves radiated through the at mosphere, and transforming said intercepted current into low frequency alternating cur rent, whereby the intercepted liigh frequency current is translated into a current that is readilyl perceptible,

In testimony whereofl affix my signa ture in presence of two Witnesses.

RUDGLF GOLDSCIIMID'I.

IVitnesses: v WOLDEMAR HAUPT, HENRY I-IAsrER. 

